1. Field of the Invention
This invention relates to a biochemical analysis apparatus for applying a liquid sample to a test film provided with a single reagent layer or a plurality of reagent layers, maintaining the test film at a predetermined temperature (i.e. carrying out incubation) for a predetermined time, and measuring the degree of color formation given rise to by a reaction of the reagent with the liquid sample during or after the incubation. This invention particularly relates to a biochemical analysis apparatus suitable for quick processing.
2. Description of the Prior Art
Qualitative or quantitative analysis of a specific chemical constituent in a liquid sample is generally conducted for various industrial purposes. Particularly, it is very important in biochemical and clinical fields to quantitatively analyze chemical constituents or physical constituents in body fluid such as blood or urine.
In recent years, as disclosed in, for example, Japanese Patent Publication No. 53(1978)-21677 and Japanese Unexamined Patent Publication No. 55(1980)-164356, there has been developed and put into practice a dry type chemical analysis slide for quantitatively analyzing a specific chemical constituent or a specific physical constituent contained in a liquid sample simply by applying a droplet of the liquid sample. With the chemical analysis slide, it is possible to analyze a liquid sample more simply and more quickly than with the conventional wet type analysis method. Therefore, the use of the chemical analysis slide is desirable particularly in medical organizations, research laboratories, or the like where many samples are to be analyzed.
In order to analyze a chemical constituent or the like contained in a liquid sample by use of the chemical analysis slide, a measured amount of the liquid sample is put on the chemical analysis slide and is maintained at a predetermined temperature (i.e. incubated) for a predetermined time in an incubator to cause a color reaction. The chemical analysis slide is then exposed to measuring light having a wavelength selected in advance in accordance with the combination of the constituent of the liquid sample with a reagent contained in the reagent layer of the chemical analysis slide, and the light reflected by the chemical analysis slide is measured in terms of the optical reflective density (hereinafter referred to simply as "optical density"). In this manner, quantitative analysis of the chemical constituent or the like is carried out.
In the medical organizations, research laboratories or the like in which many liquid samples are to be analyzed, it is desirable that the analysis be conducted automatically and sequentially. To satisfy this need, there have been proposed various chemical analysis apparatuses for carrying out sample analysis automatically and sequentially by use of the aforesaid chemical analysis slides. One of such chemical analysis apparatuses is disclosed in, for example, Japanese Unexamined Patent Publication No. 56(1981)-77746. Also, as a means for analyzing liquid samples automatically and sequentially, there has been proposed in, for example, U.S. Pat. No. 3,526,480 an apparatus wherein a long tape-like test film containing a reagent is accommodated instead of the aforesaid chemical analysis slides, and sample application, incubation and measurement are carried out sequentially by pulling out the test film.
The technique using the chemical analysis slide has the drawback that the chemical analysis slide requires a high manufacturing cost and the running cost of the apparatus is high. Also, with this technique wherein a single chemical analysis slide is used for a single measurement, many chemical analysis slides must be processed for automatically and sequentially carrying out the analysis of liquid samples, and therefore the apparatus becomes complicated, large and expensive. On the other hand, the technique wherein the long tape-like test film is used is advantageous in that the running cost is low and measurement can be carried out automatically and sequentially. However, in the case of an apparatus wherein a sample-applied portion of the long test film is conveyed into an incubator provided at a position different from the sample application and incubated in the incubator after the liquid sample is applied to the test film, the test film must be pulled out over a long length for the purpose of conveyance of the test film into the incubator, and therefore the test film cannot be utilized efficiently. Also, at the time the long test film is to be loaded into the apparatus, it is necessary to carry out the operations of fitting a feed reel around which the unused long test film is wound and a wind-up reel around which no long test film has been wound to the apparatus and winding a leading edge portion of the long test film around the wind-up reel. At the time the long test film is to be discarded after being used, it is necessary to carry out the operations of disengaging the wind-up reel from the apparatus and then removing the feed reel from the apparatus. Such processing of the long test film is troublesome.